The sky and the ground at a location may be idealized as a black hemispherical surface at temperature 18°C placed over a large horizontal gray surface of emissivity 0.75 and temperature 28°C....

The sky and the ground at a location may be idealized as a black hemispherical surface at temperature 18°C placed over a large horizontal gray surface of emissivity 0.75 and temperature 28°C. Calculate the steady rate of heat loss per unit area from the ground to the sky.